Posted
by
samzenpuson Thursday July 03, 2014 @12:32AM
from the breathing-easy dept.

sciencehabit writes A "superathlete" gene that helps Sherpas and other Tibetans breathe easy at high altitudes was inherited from an ancient species of human. That's the conclusion of a new study, which finds that the gene variant came from people known as Denisovans, who went extinct soon after they mated with the ancestors of Europeans and Asians about 40,000 years ago. This is the first time a version of a gene acquired from interbreeding with another type of human has been shown to help modern humans adapt to their environment.

There is another obvious point in history where such a gene transfer could have occurred. European conditions favour light skin, and Neandertals had been hanging out there for some tens of thousands of years before modern humans turned up and so had evolved light skin. These newcomers, having recent ancestry in Africa, were probably dark skinned. Interbreeding could easily have introduced the beneficial-to-European-conditions light skin mutations into the modern population.

My memory of the literature (which I have followed just a little bit, not closely) is that this did not happen - genetic analysis shows that modern Europeans and Neandertals acquired light skin through different mutations. However, Wikipedia [wikipedia.org] says this is still under debate.

Who is to say some of the Neanderthal genes that have been found in humans are not "helpful"? How are they measuring "helpful adaptation"? Perhaps they mean the high-altitude features are clearly helpful, while the benefits of others are not known yet. (Maybe some of the top football players are the top because of Neanderthal genes.)

A significant number of those Neanderthal and Denisovan genes are thought to be very helpful. For example Neanderthal genes are thought to play an important part in the way skin works in modern Europeans/Asians/Native Americans/Australians (cold climate tolerance, resistance to some diseases, synthesis of vitamins). However, having strong suspicions that this is the case because a whole bunch of skin related DNA in these populations seems to have come from Neanderthals and Denisovians and suspecting that this DNA is important because Neanderthal and Denisovan DNA seems to have been 'selected out' of some other parts of the genome but is still there in the skin related regions of the genome is one thing. Proving it scientifically is a whole other matter. These guys simply managed to become the first to prove in a scientifically rigorous way the helpfulness of one of the numerous bits of Neanderthal/Denisovan DNA suspected to be beneficial. Now let's hope this stands up to peer review.